BMP Web App

As a user, I want to register securely using my email, phone number, and display name so that I can create a new account in the app.

API Flow
Check username availability
Initiate email verification and send OTP
Check phone availability
Verify email OTP
Verify phone with Firebase token
Complete registration with display name

Acceptance Criteria

Registration completes only after required verifications
App sends valid session_id and display_name
Success response stores auth/session data if returned
User is redirected to home/dashboard/onboarding completion screen
Failure state handled clearly

Register Subtasks
Create request/response models for all register APIs
Add repository methods for each endpoint
Add state management for loading/success/error states
Persist session_id safely between steps
Validate email, phone, username, and display name
Handle update-required response (426)
Add logs for request, response, and failure cases
Map backend messages to user-friendly UI messages